Power-transmission control



Sept. 11,1923.

I W. A. STEVENS POWER TRANSMISSION CONTROL Filed Oct. 4. 1921 2 Sheets-Sheet 1 I Z, A t/ w Sept. 11,1923. 1,467,958 w. A. STEVENS POWER TRANSMISSION CONTROL Filed 001,. 4. 1921 2 Sheets-Sheet 2 field winding Patented Sept. 11, 1923.

1 UNITED STATES,

WILLIAM ARTHUR STEVENS, OF MAIDSTONE, ENGLAND. 1'

POWER-TRANSMISSION oonrnon Application filed October 4, 1921 Serial Ho. 505,231;

To all whom it may concern Be it known that 1, WILLIAM ARTHUR S'rEvnNs, a subject of the King of Great Britain and Ireland, residing at Maidstone. in the county of Kent, England, have invented Improvements in or Relating to Power-'lransmission Controls, ofwhich the following is a specification. ,Inthe specification of my Letters'Patent No. 1398656, there is described an electrical transmission arrangement, specially applicable for motor vehicles,'comprising an electric generator driven by a prime mover for supplying current to a series wound electric motor, the generator being provided with shunt and series field windings of which the series winding can, by means of a circuit controller, be connected as a shuntto the motor series winding, and the current through the said generator series winding can be varied by a variable resistance from maximum to zero, according to the requirements of the electric motor, or according to the requirements of a lighting, welding or likecircuit when the arrangement is used for lighting or welding purposes, the circuit controller being also adapted to reverse the direction of the current through the series of the motor for forward. and backward running. j Now the present invention has reference to improvements in electrical transmission arrangements of the kind referred to and it has for its principal object so to construct such an electrical transmission arrangement vthat the circuits through the armatures of the generator and motor will not at any time be broken by the circuit controller used in such an arrangement, and that movement of the controller from eitherits forward or' backward position, for forward or backward running of the motor, to the central or neutral position, will short. circuit the series field Winding of the generator and also that of the motor.

For this purpose the circuit controller and H of the apparatus in the forward running position, in the neutral or lighting position and in the reverse running position respectively. Figs. 4;, 5 and 6 are diagrammatic Views showing an electrical transmission arrangement of the kind referred to embody ing another modified construction of circuit controlle13for enabling the object of the present invention to be attained, the circuit controller being shown in three different positions. in the three figures.

Referring to Figs. 1, 2 and 3, a is theelectrio generator, 6 its series field winding and If its shunt winding. c is the electric motor and 61 its series field winding. A is a prime mover for driving the electric generator. 9 and it are respectively the stationary and movable portions of a variable electrical resistance device. .25 and u are the insulated movable contacts, in the form of metal segments, and o, w, as and y'the insulated stationary contacts, of a circuit controller of the type described and shown in my afore said patent but modified according to the present invention to enable the object thereof to be attained.

According to the present invention instead of making the segment u to extend through an angular width of only about 150, as before, Whilst segment It extends through an angular width of about 210, it is made to extend through a greater angular width, sayi'of about 210, like segmentt, so that in the central or neutral position ofthe controller, shown in Fig. 2, contacts '0 and a will bear against segment t and contacts 00 and 12 willbear against segment a. As will be obvious,.the segments t and uimay be made; 16 different angular widths in that mentloned so long as the condition mentioned, obtains. Contact e which is connected to contact 3 as before, is new connected to the positive pole ofthe electric generator. a and contact to, which is connected to contact a and to the movable member of the variable resistance device 9, h, as before is'now connected to the negativejpoleof the electric motor 0, the other poles of the generator and motor being ar ranged to be connected together, as through a change over swltchc'y Also, the segments 15 and 11, instead or being connected, the former to one pole, say the positive pole of the electric generator w and the other to one pole, say the l figi -ti-ve pole of the motor a,

as in the former arrangements are respea tively connected to the two ends of the series field winding (Z of the electric motor. As will be seen the arrangement is such that when the circuit controller is in its said centralor neutral and lighting position (Fig. 2), the stationary contacts o and to will bear on segment t, and the stationary contacts and 7 will bear on segment 11, with the result that the series field windings 7) and (Z of the electric generator (6 and motor (2 respectively are both short circuited, the variable resistance device 71- 9 being likewise short circuited with the winding 7) and that when the controller is moved trom either its il'orward running position (Fig. 1), or its rearward po- Sition (Fig. for forward or rearward running of the motor respectively to its central or neutral position (Fig. 2) it will not break the circuit through the armatures of the generator-and motor. The Full line arrows show the direction ot the current through the electric. generator a, generator series field winding 7), variable resistance g t and electric motor 0. The dotted line arrows show the direction or the current thrmigh the generator (4, motor series field winding (1 and elcctric motor 0.

In the modified construction oi circuit controller shown in Figs. 4, 5 and 6, the tour stationary insulated contacts are made as tour circular metal segments r 10 m and 7 arranged concentrically to a =common axis upon a base 13 with a cap C between the ends of adjacent segments, so that each segment is oi an angular width ol less than 90. Associated with these stationary segments are two insulated movable circular metal contact segmentsif and usecured. to a rotary carrier D, so as to he concentric to the same axis as the stationary contacts o w, m and y and having a gap E between their adjacent ends so that each of them is of an angular width less than 180 but oi. greater angular width than each of the stationary scg-' -n1ents.

Megn'ients o and w are arranged opposite to each other and connected respectively to the positive pole of the electric generator a and the movable member 71/ of the variable resistance device the stationary member 9 of which is connected to one end of the generator series winding 2) the other end of which is connected to the said positive pole of the electric generator a, segment ve being also connected to one pole namely say the negative pole of the electric motor 0 the other pole of which can be connected to the second pole of the generator at by a change over switch Segments m and 7 are arranged opposite each other and c0nnected to the respective ends of the-motor series field winding (Z.

As will be seen the arrangement is such that in one position of the movable segments t a namely that shown in Fig. 4, segment I? connects segments 10 and g and arinatures of the generator segment u connects segments o and .60, thus connecting the motor series field winding (1 in series with the motor 0 and in parallel with the generator series field winding Z) for forward running of the motor. In another position of the two movable segments 23 and a namely that shown in Fig. 5. the generator series field winding I) and also the motor series field winding (1, are both short circuitcd by the two movable segments t u bridging all the stationary segments n, 10 m and 1 In. a third position shown in Fig. 6 segment t connects scgmeats in" and .11 and segment '21" connects segments o and so as again to connect the motor series winding (Z in series with the motor 0 but in the reverse direction, for reverse running, and in parallel with the generator series field winding b.

In each arrangement. when it is desired to adapt the same for supplying a lighting, welding or other circuit with current, two insulated terminals j and 7c are provided. one of them namely 7', being connected to the generator series field winding circuit between the winding 7) and the variable resistance device (7 71, as before. but the other in being normally disconnected but arranged tov be connected to the negative pole of the generator (4 by the change over switch 2' which at the same time opens the circuit between the generator (I. and motor c.

hat I claim is 1. In an electrical transmission arrangement of the kind herein referred to, comprising an electric generator having shunt and series field windings, a motor having a series field winding and a variable resistance device in series with the generator series field winding, a circuit controller com- .prising stationary and movable contacts and adapted in one position to effect forward running ot the motor, in another position to efiiect reverse or backward running of the motor, and in an intern'iediate neutral position to short circuit the generator series field. winding and resistance device and also to short circuit the motor series field winding, and to maintain the circuit through the and motor un either the forposition to the broken when moving from ward or backward running intermediate position.

9'. In an electrical transmission arrangement oil the kind herein rc'lcrred to, comprising an electric generator having shunt and. series field windings. an electric motor having a series field winding, and a variable resistance device in series with the generator series field winding, a circuit controller comprising movable and stationary contacts adapted in one position of the movable contacts to short circuit both the generator series field. winding and also the motor series field winding, in another position of the said movable contacts to connect the generator series field winding in series with the motor and the motor field winding in parallel with the generator series field winding for for- Ward running of the motor, and in a third position of the movable contacts to connect the generator series field wlnding in series with the motor, and the motor series field winding in parallel with the generator series field winding, but in the reverse direction, for reverse running of the motor, and in moving from one position to the other, to maintain the circuit of the generator and motor unbroken.

3. In an electrical transmission arrangement of the kind herein referred to, comprising an electric generator having a shunt and a series field winding, a motor having a series field winding and a variable resistance device in series with the generator series field winding, a circuit controller comprising tour stationary segmental circular contacts 0 20 m and 3 and two movable segmental circular contacts t and n adapted to bear against the stationary contacts, one stationary contact 0 being connected to the positive pole of the generator, another stationary contact w being connected to the negative pole of the motor and to one terminal of the resistance device the other terminal of which is connected to one terminal of the generator series field winding the other terminal of which is connected to the positive pole of the generator, two of said stationary contacts 00 and g being connected to the opposite terminals of the motor field winding, and said movable contacts t and u when moved into their mid position, respectively connecting three of said stationary contacts w 00 y and two of the last mentioned contacts together with another stationary contact 12 m and when moved into a position to one side of the mid position, respectively connecting two each of said stationary contacts Q01, y and o 00 so as to effect iiorward running of the motor, and when movedinto a position to the other side of the mid position, respectively connecting another two each of said stationary contacts w 00 and '0 7/ so as to e'fi'ect backward running of the motor.

4. In an electrical transmission arrangement of the kind herein referred to, com prising an electric generator having shunt and series field windings, a motor having a series field winding and a variable resistance device in series with the generator series field winding, a circuit controller com prising stationary and movable contacts and adapted in one position to effect forward running of the motor, in another position to effect reverse or backward running of the motor and in an intermediate neutral position to short circuit the generator series field winding and resistance device and also to short circuit the motor series field winding and to maintain the circuit through the armatures of the generator and motor unbroken when moving from either the forward or backward running position to the intermediate position, a pair of insulated terminals, one connected to the lead between'the generator series field winding and the variable resistance and a switch adapted in one position to connect the armatures of the generator and motor in series and in another position to open the circuit between the generator and motor armature and connect the second terminal to the pole of the generator to which the motor was previously connected.

Signed at London, England, this 15th day of September, 1921.

WILLIAM ARTHUR STEVENS. 

